63results about How to "Increase Al-Si Ratio" patented technology

The invention provides a method for producing alumina and co-producing active calcium silicate with high-alumina fly ash. The steps include: first reacting high-alumina fly ash with sodium hydroxide solution to perform pre-desilication to obtain liquid-phase desiliconization liquid and Desiliconized fly ash in solid phase; add milk of lime to the desiliconized liquid for causticization reaction, the solid phase is active calcium silicate, and the finished product is obtained by pressure filtration and flash drying; add limestone and carbonic acid to the desiliconized fly ash The sodium solution is formulated into a qualified raw slurry, and then the qualified raw slurry is roasted into clinker, and the liquid phase dissolved in the clinker is sodium aluminate crude solution; the sodium aluminate crude solution is desiliconized, carbonized, and seeded in the first and second stages. Metallurgical grade alumina that meets the requirements can be obtained after processes such as calcination and roasting. The invention overcomes the defects in the prior art, realizes less material flow and slag formation, relatively low energy and material consumption and production costs, high alumina extraction rate, and co-produces active calcium silicate with high added value, which can be used Widely used in chemical industry.

The invention relates to a method for the comprehensive application of fly ash or slag, in particular to a method for the predesilication of the fly ash or the slag. The method mainly comprises the process flows including the baking and the activation of the fly ash or the slag, the formula process of the raw meal of activated the fly ash or the slag and a sodium hydroxide solution and the production of white carbon black. Through adopting a technological line during which the fly ash or the slag are baked and activated at first and then a sodium hydroxide solution is used to extract noncrystalline silicon oxide at a low temperature, the method ensures that the mass ratio of aluminum oxide and silicon oxide of desilicated fly ash reaches to 2.14; therefore, the method breaks a new path totake the fly ash or the slag as a raw material source for extracting metallurgical-grade aluminum oxide, thereby increasing the comprehensive utilization value of the fly ash and the slag.

This invention discloses a method for extracting SiO2 and Al2O3 from fly ashes. The method comprises: activating fly ashes, leaching with more than 40 wt. % NaOH solution so that Si is stripped out in the form of sodium cilicate, introducing CO2 to prepare SiO2, adding CaO or CaCO3 into the leaching residue, calcining to obtain a clinker, preparing Al2O3 by Bayer method, and preparing cement from the waste residue. The method extracts Si at first, thus increasing the Al / Si ratio in the leaching residue. Treated leaching residue can be directly subjected to Bayer method to extract Al2O3, which largely simplify Al2O3 extraction process and increase Al2O3 utility. The method has such advantages as simple process, low investment, and high product added value.

The invention provides a method for extracting aluminum oxide from coal gangue and co-producing active calcium silicate, and relates to the technical field of producing aluminum oxide and the active calcium silicate. The method comprises the following steps of: grinding coal gangue, and roasting and activating the ground coal gangue; performing alkali soluble desilication of coal gangue clinker to obtain desilication coal gangue and solution of sodium silicate; performing causticizing reaction of the solution of sodium silicate to obtain water-containing calcium silicate and solution of sodium hydroxide, and drying the water-containing calcium silicate to obtain micro powder of active calcium silicate; adding limestone and solution of sodium carbonate into the desilication coal gangue, and ball-grinding the mixed solution to obtain raw slurry; dissolving out the clinker which is obtained by roasting the raw slurry with water to obtain crude solution of sodium aluminate and silicon andcalcium residues, wherein the silicon and calcium residues can be used as cement raw materials after post-treatment; performing deep desilication of the crude solution of sodium aluminate to obtain the purified solution of sodium aluminate; feeding CO2 into the purified solution of sodium aluminate to obtain aluminum hydroxide and solution of sodium carbonate; and calcining the aluminum hydroxideto obtain the aluminum oxide products. The method has the advantages of simple process, low production cost, low energy consumption and little consumption of raw materials; in addition, by the method, two kinds of silicon-containing byproducts are simultaneously produced, and no waste is generated.